After finishing second at the 1927 Premier Pas Dunlap race and then competing at the 1928 Olympics, Henri Lemoine turned professional and had a very long career, competing through 1958, when he was almost 50-years-old. He rode many varied races, competing in six-days and on the road, but was likely best known as a track racer in the motor-paced event. He was a six-time French professional champion in motor-paced, winning in 1938, 1942, 1945, and 1951-53, and standing on the podium 14 times in the event. He competed in six-day races from 1930-37, both in the United States and Paris, and his last known competitive appearance came at the 1958 Buenos Aires Six-Day. On the roads, Lemoine placed second at the Critérium des As in 1930 and 1931, placed 11th at the 1932 Critérium Internationale, and 20th at the 1933 Grand Prix des Nations.
France